I'm a 38" chest and get my shirts in 42.5". Took a few tries to get it right. As for the waist, I'm still figuring that one out haha; I'm a 32" waist and might try 36" next. As for shoulders, I go normal because I prefer comfort and flexibility in the shoulders. My main issue is the forearms. I already go traditional and I don't want to keep increasing bicep measurement because the sleeves will be too baggy then

It hasn't been offered before but it was previewed as part of their fall/winter 2014 collection as seen in this article: http://www.selectism.com/2014/03/19/oak-street-bootmakers-fw2014/#slide-6. It seems like OSB is rolling it out slowly starting with the trapper boot.